Naturally occurring osteoporosis is associated with increased fracture risk, including vertebral crushing. Bone Mineral Density (BMD) measured using Dual-Energy X-ray Absorptiometry (DEXA) is the established standard for defining osteoporosis and relative fracture risk. This method, however, examines only bone quantity and not trabecular bone architecture / quality which are also implicated in increased fracture susceptibility. This study compares data from DEXA and micro-CT to assess the relative fracture risk predictability of each. The last lumbar vertebral body, from 36 female free-ranging rhesus macaques (5.4 to 23.7 years) from Cayo Santiago, PR was examined. Results showed a 0.80 correlation between areal BMD (g/cm2) from DEXA (Lunar) and the closest equivalent volumetric micro-CT (SCANCO) value (mg/cm3). Multivariant analysis [a=0.05] of micro-CT trabecular structure and architecture revealed bone density is most highly correlated with trabecular thickness (0.94) and bone volume ratio (0.99). Correlation between bone density and other bone architectural elements, e.g., connectivity, bone surface ratio, and number of trabeculae, was not significant. Neither morphology nor BMD revealed significant differences between last vertebrae of individuals with or without fractures elsewhere in the vertebral column. The results of this study show DEXA as a less perfect measure of actual bone density than micro-CT which also provides insight into trabecular structure to help assess osteoporotic status and relative fracture risk. [Support: University of Calgary, University of Toronto, UPR RR03640 & RR03051]